Rather than focus on where we disagree, let's look at where we agree.
I think we could have a couple of 'forms' trees, where say one focuses on attack, and one on defense - perhaps something along the lines of Soresu form being a 15xp talent, where you commit a force die to increase your defenses by 1 as long as lightsaber is held activated? And for a 25xp talent Improved Soresu, where it's +2 instead?
That was sort of what I was thinking. The similar forms could be grouped together into a spec/power tree/advanced whatever, leaving us with something like 3 or 4 to choose from. We don't need a bajillion forms to choose form that are only slightly different from one another, when those differences can be represented by the sum of using different talents.
I think they will make starting characters from each book compatible but I don't see why a lightsaber is out of the question.
Every other book opens up the iconic gear/equipment/ship that's required for the careers to work well at character creation.
Simple. A lightsaber is 10 grand worth of personal gear , for a weapon that does far more damage than almost everything else, crits more easily than anything else, and can cut through other weapons like butter. Where as in EoE, everyone gets a seat on a ship, or in AoR, everyone gets a room in a base or half of a Y-Wing to borrow. It's not the same because those things are group assets. F&D will likely still give some kind of transport option, but I highly doubt that over 10 grand in credits is going to get handed out just because Jimmy wants to pretend he's an extinct and incredibly illegal space wizard.
Plus, there is nothing to say that you can start as a Jedi, canonically or based on precedent. Not only are the Jedi extinct, but FFG has would be invalidating a great deal of material by making a Jedi career. We'll know more in a week or so, but I continue to doubt the Jedi career wishlist because it isn't based on evidence. And without a Jedi career, there is no reason for anyone to start with a lightsaber. Does that answer why it's out of the question?